The significant rise in earthquakes along one stretch of the state has prompted regulators in Oklahoma to order oil and gas companies to seriously cut back on injecting wastewater into the earth.

The Oklahoma Corporation Commission wants energy corporations to reduce the amount of wastewater injection by 38% in a 40-mile stretch northeast of Oklahoma City. That area experienced 359 earthquakes of magnitude 2.5 or greater in 2014 after only 14 the year before that. This year’s total is on track to be 20% higher, according to The New York Times.

Reuters reported that the earthquakes aren’t related to hydraulic fracturing, or fracking. It’s the re-injection of saltwater that is pumped out of wells along with oil and gas.

The amount of wastewater being injected in the area is not significant, according to the commission. Only 8.8 million barrels of wastewater out of 1.1 billion barrels statewide were disposed of there in 2013.

“The seismicity is off the charts, and we don’t have any high-volume wells there,” Tim Baker, director of the commission’s Oil and Gas Conservation Division, told the Times. “So we’ll go ahead and reduce the volume and see if that has any effect on seismicity.”